Banks Spar Over Accounting
In Merger of Japanese Giants

TOKYO -- A battle is brewing behind one of Japan's biggest mergers this year, illustrating a shift in the way deals are getting done in corporate Japan.

Last year, two of Japan's biggest chemical makers -- Sumitomo Chemical Co. and Mitsui Chemicals Inc. -- each hired a Wall Street investment bank to help steer them through a $10 billion merger. The deal was considered a watershed in a slowly changing financial landscape. In the past, Japanese companies typically merged without advisers, or have hired an investment bank to...